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Biomedical subjects

G Klein

Publications and source records attributed to G Klein.

At least 37 records · Page 2Linked to original sources
PubMed1998

Adhesive interactions of human multiple myeloma cell lines with different extracellular matrix molecules.

Multiple myeloma represents a human B cell malignancy which is characterized by a predominant localization of the malignant cell clone within the bone marrow. With the exception of the terminal stage of the disease the myeloma tumor cells do not circulate in the peripheral blood. The bone marrow microenvironment is believed to play an important role in homing, proliferation and terminal differentiation of myeloma cells. Here we have studied the expression of several extracellular matrix (ECM) molecules in the bone marrow of multiple myeloma patients and analyzed their adhesive capacities with four different human myeloma-derived cell lines. All ECM molecules analyzed (tenascin, laminin, fibronectin, collagen types I, III, V and VI) could be detected in bone marrow cryostat sections of multiple myeloma patients. Adhesion assays showed that only laminin, the microfibrillar collagen type VI and fibronectin were strong adhesive components for the myeloma cell lines U266, IM-9, OPM-2 and NCI-H929. Tenascin and collagen type I were only weak adhesive substrates for these myeloma cells. Adhesion to laminin and fibronectin was beta 1-integrin-mediated since addition of anti-beta 1-integrin antibodies could inhibit the binding of the four different cell types to both matrix molecules. In contrast, integrins do not seem to be involved in binding of the myeloma cells to collagen type VI. Instead, inhibition of binding by heparin suggested that membrane-bound heparan sulfate proteoglycans are responsible ligands for binding to collagen type VI. Adhesion assays with several B-cell lines resembling earlier differentiation stages revealed only weak interactions with tenascin and no interactions with collagen type VI, laminin or fibronectin. In summary, the interactions of human myeloma cells with the extracellular matrix may explain the specific retention of the plasma cells within the bone marrow.

Animals↗
PubMed1998

Open state block by fendiline of L-type Ca++ channels in ventricular myocytes from rat heart.

The effects of fendiline on L-type Ca++ currents [ICa(L)] were investigated in rat ventricular cardiomyocytes using the patch-clamp technique both in the whole-cell disrupted-patch and in the cell-attached configuration. For comparison, the effects of verapamil were also investigated. Both compounds depressed the magnitude of whole cell ICa(L), verapamil being about 15 times more potent than fendiline. Verapamil did not change the time course of the current, whereas fendiline accelerated its decay when either Ca++ or Ba++ ions were used as charge carriers. In the presence of the Ca++ agonist BayK8644 (10 microM), the potency ratio of fendiline/verapamil was inverted. BayK8644 (10 microM) also reversed the potency ratio of verapamil/fendiline in smooth muscle, with respect to changes in tension induced by K+ (48 mM). In single channel recordings at 0.1 Hz, in the presence of BayK8644 (1 microM) and using Ba++ ions as the charge carrier, fendiline (1 microM) reduced mean open time by 34% and channel availability by 8%; the ensemble average current of Ca++ channels was reduced by 43%. In the same experimental conditions, verapamil (1 microM) was ineffective. These results can be explained by the assumption that fendiline blocks Ca++ channels preferentially in the open state, in contrast to verapamil which blocks preferentially inactivated Ca++ channels.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1998

Clinical performance of the new cardiac markers troponin T and CK-MB on the Elecsys 2010. A multicentre evaluation.

Elecsys assays for the cardiac markers Troponin T (cTnT) and CK-MB have been evaluated in an international multicenter study on the random access analyzer Elecsys 2010 to characterize their clinical performance and their comparability with respective established routine methods. In method comparison studies of Elecsys Troponin T (TnT) with Enzymun-Test TnT, good correlations (r > or = 0.95) and a high degree of correspondence (slopes in 4 laboratories between 0.95 and 1.05) were found. The method comparison studies of Elecsys CK-MB with various CK-MB routine methods lead to good correlations but some systematic deviation in the slopes due to varying standardization. In a reference population of 350 persons upper reference limits (97.5th percentile) of 0.03 milligrams/l for Elecsys TnT and 3.1 milligrams/l for Elecsys CK-MB were found. In cardiosensitivity studies the equivalent diagnostic information of the new Elecsys assays to routine methods was confirmed in the early diagnosis of acute myocardial infarction (AMI), the detection of minor myocardial damages in patients with unstable angina pectoris (UAP) and in time course data monitoring of AMI and bypass surgery patients. The superior sensitivity of cTnT versus CK-MB has been established in a screening situation where in 29 patients with cardiac diseases only cTnT, but not CK-MB, was found pathologically increased; this was due either to the larger diagnostic window of cTnT in AMI or to the more sensitive recognition of minor myocardial damage. In the same study, the cardiospecificity of Elecsys TnT was found to be at least 99.5%. This has also been demonstrated in an earlier study for Enzymun-Test TnT. Further cardiospecificity testing, e.g. in renal failure patients, showed results equivalent to those of Enzymun-Test TnT. An extended clinical study involving 294 patients with chest pain, of whom 58 had a final diagnosis of AMI, revealed highly comparable sensitivity and specificity for the Elecsys assays and routine methods. Thus, the already recommended clinical cut-off values of 0.1 milligrams/l for cTnT and 5 milligrams/l for CK-MB are also valid for the Elecsys assays. The slightly improved sensitivity of Elecsys TnT in the lower range even allows the recognition of pathological increase at cTnT concentrations below 0.1 milligrams/l in special situations with sufficient additional clinical information. Summarizing, provide the two cardiac markers on the Elecsys 2010 at least equivalent or even superior diagnostic information in various clinical situations of cardiac disease compared with routine methods. The short turn-around time and reliable performance qualify the Elecsys assays as new methods of choice for routine and emergency use.

Adult↗
PubMed1998

Cloning of the groE operon of the marine bacterium Vibrio harveyi using a lambda vector.

groES and groEL genes encode two co-operating proteins GroES and GroEL, belonging to a class of chaperone proteins highly conserved during evolution. The GroE chaperones are indispensable for the growth of bacteriophage lambda in Escherichia coli cells. In order to clone the groEL and groES genes of the marine bacterium Vibrio harveyi, we constructed the V. harveyi genomic library in the lambdaEMBL1 vector, and selected clones which were able to complement mutations in both groE genes of E. coli for bacteriophage lambda growth. Using Southern hybridization, in one of these clones we identified a DNA fragment homologous to the E. coli groE region. Analysis of the nucleotide sequence of this fragment showed that the cloned region contained a sequence in 71.7% homologous to the 3' end of the groEL gene of E. coli. This confirmed that the lambda clone indeed carries the groE region of V. harveyi. The positive result of our strategy of cloning with the use of the genomic library in lambda vector suggests that the same method might be useful in the isolation of the groE homologues from other bacteria. The V. harveyi cloned groE genes did not suppress thermosensitivity of the E. coli groE mutants.

Bacteriophage lambda↗
PubMed1997

NotI linking/jumping clones of human chromosome 3: mapping of the TFRC, RAB7 and HAUSP genes to regions rearranged in leukemia and deleted in solid tumors.

By applying the 'recognition mask' strategy to 300 mammalian sequences containing NotI sites we demonstrated that 5' ends of genes are highly enriched in NotI sites. A NotI linking clone NL2-252 (D3S1678) containing transferrin receptor (TFRC) gene was used as an initial point for chromosomal jumping. One of the jumping clones, J21-045 traverses 210 kbp and links NL2-252 to NL26 (D3S1632), a NotI linking clone containing highly polymorphic sequences. The TFRC gene was mapped to 3q29, close to the telomeric marker D3S2344, by linkage analysis, a panel of hybrid cell lines, GeneBridge 4 panel and FISH. Clone NLM-007 (D3S4302) was found to contain ras-homologous gene RAB7. By FISH and a panel of hybrid cell lines this gene was mapped to 3q21. This region is of particular interest due to frequent rearrangements in different types of leukemia. Clone L2-081 (D3S4283) containing new member of ubiquitin-specific proteases (HAUSP gene) was localized in 3p21 inspiring further investigation of involvement of this gene in development of lung and renal carcinomas.

Chromosome Mapping↗
PubMed1997

Lack of correlation between EBV serology and presence of EBV in the Hodgkin and Reed-Sternberg cells of patients with Hodgkin's disease.

Epstein-Barr virus (EBV) is detected in Hodgkin and Reed-Sternberg (HRS) cells in up to 50% of patients with Hodgkin's disease (HD). HD patients have been reported to express high serum titers against EBV antigens, even prior to the diagnosis of HD. Patients with high serum titers have a poorer prognosis. The aim of this study was to examine the relationship between the presence of EBV in HRS cells and the antibody titers reactive with different EBV antigens. Frozen serum and histopathological tissues were available from 107 untreated HD patients diagnosed between 1979 and 1991. The presence of EBV in the HRS cells was evaluated with immunohistochemistry directed against the LMP-1 antigen and/or with in situ hybridization of EBER-1. Analyses were performed of serum titers against early antigen (EA), diffuse (IgA and IgG) and restricted (IgG), virus-capsid antigen (VCA) (IgA and IgG), and EBV-encoded nuclear antigens (EBNA, EBNA 1, EBNA 2A, EBNA 2B, EBNA 6). EBV was detected in 27/107 (25%) tumor specimens, with a higher proportion in the MC group 8/13 (62%) (p < 0.01). IgG VCA and EBNA were detected in 99/107 (93%), evidence of a previous EBV infection. There were no significant relationships between antibody titers reactive with different EBV antigens and detectable EBV in HRS cells. Furthermore, there did not appear to be any relationship between EBV serology or the presence of EBV in HRS cells and clinical outcome. The role of EBV in the development of HD, especially its relationship to the immunological response, remains unclear.

Adult↗
PubMed1997

Autologous lymphokine-activated killer cell therapy of Epstein-Barr virus-positive and -negative lymphoproliferative disorders arising in organ transplant recipients.

Lymphoreticular malignancies, collectively called posttransplant lymphoproliferative disorders (PTLD), eventually develop in 2-5% of organ transplant recipients. They frequently undergo regression when immunosuppression is reduced or stopped. This feature has been associated with a previous or de novo Epstein-Barr virus (EBV) infection. We herein describe immunotherapy with autologous lymphokine-activated killer (LAK) cells in seven patients with PTLD (four EBV-positive patients and three EBV-negative patients). Autologous peripheral blood mononuclear cells were obtained by leukapheresis, depleted of monocytes, and cultured in the presence of interleukin 2 for 10 to 11 days. A single dose of 5.2 x 10(9) to 5.6 x 10(10) LAK cells was given intravenously. Systemic interleukin 2 was not administered. The four patients with EBV+ PTLD had complete tumor regression; two of them developed controllable rejection. Three patients are well 13-16 months after treatment; the fourth patient died of pneumonia 41 days after infusion. Three patients with EBV- lymphomas had no response despite prior evidence that their tumors also were subject to immune surveillance. Two of these three patients died after being given other treatment, and the third patient has persistent tumor. In conclusion, autologous LAK cell infusion was effective for treatment of four EBV+ organ transplant recipients. LAK cell efficacy for three patients with EBV- PTLD was not evaluable under the management circumstances in which this treatment was utilized.

Adult↗
PubMed1997

Epstein-Barr virus (EBV) gene expression in lymphoid B cells during acute infectious mononucleosis (IM) and clonality of the directly growing cell lines.

We examined the patterns of viral gene expression in acute infectious mononucleosis (IM) patients and the clonality of the directly growing EBV-carrying cell lines. Both low- and high-density EBV-carrying B cells obtained from the patients' tonsils expressed EBNA1, EBNA2 and LMP1. Like LCLs and immunoblastic B-cell lymphomas, the in vivo EBV-carrying low-density cells used only the latency III program for viral gene expression. The in vivo EBV-carrying high-density B cells used both the latency I program, as indicated by the QUK-, and the latency III program, as indicated by the YUK-EBNA1. This suggests that the lymphoid tissues contained not only proliferating immunoblasts but also cells programmed for latent viral persistence in vivo. EBV-carrying cells that grew directly into permanent cell lines in the presence of virus-neutralizing antibody and a late viral inhibitor were polyclonal, as indicated by JH rearrangement. Two of the high-density-derived lines had identical JH and TR patterns, indicating a common parental origin. Our investigation indicates that EBV-carrying cells divide and survive in a fully competent immune system during the outbreak of acute IM.

Antigens, Viral↗
PubMed1997

[Double-blind comparative study of the effectiveness and tolerance of 900 mg dexibuprofen and 150 mg diclofenac sodium in patients with painful gonarthrosis].

In this randomized double-blind, parallel-group study the efficacy of 300 mg oral dexibuprofen three times daily and 50 mg oral diclofenac sodium three times daily was tested for equivalence in 110 patients with painful osteoarthritis of the knee. During the 15-day treatment period the functional index for knee osteoarthritis according to Lequesne was improved under dexibuprofen by a mean of 7.4 and by a mean of 7.3 under treatment with diclofenac sodium. The test for equivalence by one-sided Wilcoxon-Mann-Whitney test shows equivalent efficacy of dexibuprofen by a Mann-Whitney-statistic of 0.505 and 0.415 as its lower boundary of the 95% confidence interval. The descriptive analysis of secondary criteria such as intensity of pain, rest pain, pain at beginning, nocturnal pain, tenderness, restriction of movement, handicap, subjective estimation of disease progression, as well as global judgement of efficacy and tolerance by investigator and patient confirm equivalence of both preparations. The pooled analysis of all parameters, tolerability included, by a Mann-Whitney-statistic of 0.520 with the lower boundary of the 95% confidence interval of 0.467 shows equivalence of both drugs with a trend to superiority of dexibuprofen due to its better tolerability. 7.3% of the patients on dexibuprofen and 14.5% of the patients on diclofenac sodium dropped out because of side-effects.

Adult↗
PubMed1997

B-CLL cells with unusual properties.

In studies concerning the interaction of B-CLL cells and Epstein-Barr virus (EBV), we encountered one patient whose cells had several unusual properties. In addition to the B-cell markers, the CLL cells expressed the exclusive T-cell markers CD3 and CD8 and carried a translocation t(18,22)(q21;q11), involving the bcl-2 and Ig lambda loci. The patient represents the 4th reported CLL case with this translocation. The CLL cells could be infected and immortalized by the indigenous and by the prototype B958 virus in vitro. The T-cell markers were not detectable on the established lines. In all experiments the immortalized lines originated from the CLL cells. Their preferential emergence over virus-infected normal B cells may be coupled to the high expression of the bcl-2 gene due to the translocation. In spite of the sensitivity of CLL cells to EBV infection in vitro, no EBNA-positive cells were detected in the ex vivo population. In vitro, we could generate cytotoxic function in T-lymphocyte cultures which acted on autologous EBV-infected CLL cells. Therefore we assume that if such cells emerged in vivo they were eliminated by the T-cell response.

Aged↗
PubMed1997

A yeast artificial chromosome (YAC) contig encompassing the critical region of the X-linked lymphoproliferative disease (XLP) locus.

X-linked lymphoproliferative disease (XLP) is characterized by a marked vulnerability to Epstein-Barr virus (EBV) infection. Infection of XLP patients with EBV invariably results in fatal mononucleosis, agammaglobulinemia, or malignant lymphoma. Initially the XLP gene was assigned to a 10-cM region in Xq25 between DXS42 and DXS37. Subsequently, an interstitial, cytogenetically visible deletion in Xq25 was identified in one XLP family, 43. In this study we estimated the deletion in XLP patient 43-004 by dual-laser flow karyotyping to involve 2% of the X chromosome, or approximately 3 Mb of DNA sequence. From a human chromosome Xq25-specific yeast artificial chromosome (YAC) sublibrary, five YACs containing DNA sequences deleted in patient 43-004 have been isolated. Sequence-tagged sites (STSs) from these YACs have been used to identify interstitial deletions in unrelated XLP patients. Three more families with interstitial deletions were found. Two of the patients (63-003 and 73-032) carried an interstitial deletion of 3.0 Mb overlapping the 43-004 deletion. In one XLP patient (30-011) who exhibited the characteristic postinfectious mononucleosis phenotype of XLP with hypogammaglobulinemia and malignant lymphoma, a deletion of approximately 250 kb was detected overlapping the deletion detected in patients 43-004, 63-003, and 73-032. A YAC contig of 2.2 Mb spanning the XLP critical region, whose orientation on chromosome X was determined by double-color fluorescence in situ hybridization and which consists of 15 overlapping YAC clones, has been constructed. A detailed restriction enzyme map of the region has been constructed. YAC insert sizes were determined by counter-clamped homogenous electric field gel electrophoresis. Chimerism of YACs was determined by FISH and restriction mapping. On the basis of lambda subclones, YAC end-derived plasmids, and STSs with an average spacing of 100 kb, a long-range physical map was constructed using 5 rare-cutter restriction enzymes. The STSs and lambda subclones were used in Southern hybridization and PCR analyses. The work presented here substantially refines the critical region for XLP. The YAC contig with the overlapping interstitial deletions constitutes the basis for the construction of a transcriptional map of the critical region and facilitates the identification of the XLP gene.

Chromosomes, Artificial, Yeast↗
PubMed1997

CD28 is not required for rejection of unmanipulated syngeneic and autologous tumors.

To gain a better understanding of the requirement of CD28 co-stimulation in different types of T cell-dependent tumor rejection responses, we performed a series of syngeneic and autologous tumor rejection experiments on CD28 knockout mice. In a preimmunization-challenge model, virally-induced ALC lymphoma and methylcholanthrene-induced MC57X fibrosarcoma transplants were rejected similarly by syngeneic CD28 knockout and immunocompetent controls. ALC-specific cytotoxic T lymphocytes (CTL) and MC57X-specific tumor necrosis factor (TNF) release were induced in CD28 knockouts, although at a reduced level in the latter case. Secondly, the spontaneous regression of Moloney murine sarcoma virus (MMSV)-induced primary tumors in the autologous hosts occurred equally in CD28 knockouts and in immunocompetent control mice. A comparable virus-specific CTL response was generated in both, as revealed in cytolytic assays against RBL-5 targets. Thirdly, the spontaneous rejection of the B7-transfected EL-4 lymphoma by immunocompetent hosts was abrogated in CD28 knockout mice, since more than 82% CD28 knockouts developed tumors after inoculation with B7-transfected EL-4 cells. Our results therefore show that CD28 co-stimulatory molecules are not required for the rejection of unmanipulated syngeneic tumors in hyperimmunized hosts and the regression of MMSV-induced sarcoma in autochthonous hosts.

Animals↗
PubMed1997

Control of B cell lymphoma recognition via natural killer inhibitory receptors implies a role for human Vgamma9/Vdelta2 T cells in tumor immunity.

The Vgamma9/Vdelta2 T cell receptor (TCR) is expressed by most human gammadelta T cells. We show here that cytotoxic T lymphocytes of the Vgamma9/Vdelta2 subset, but not of the Vdelta1 subset of human gammadelta T cells, express natural killer inhibitory receptors (KIR) with specificity for different HLA class I alleles that down-regulate TCR-mediated signaling in response to HLA class I-expressing B cell lymphomas. Vgamma9/Vdelta2 T cell clones with a T helper cell phenotype lack KIR and produce lymphokines in response to most human B cell lymphomas, just as they do upon recognition of the HLA class I-deficient human Burkitt's lymphoma Daudi. Thus, human Vgamma9/Vdelta2 T cells have an innate specificity for nonpolymorphic cell surface structures expressed by many lymphoma cells and their cytotoxic activity is controlled by KIR. These results imply a general role of human Vgamma9/Vdelta2 T cells in the defense against hematopoietic tumors that is distinct from NK cells.

Cells, Cultured↗
PubMed1997

An association between the flat back and postpolio syndromes: a report of three cases.

The cases of three patients with a history of paralytic poliomyelitis in childhood who developed the flat back syndrome before or after spinal fusion for degenerative disease as adults were reviewed. The flat back syndrome, a combination of an inability to stand erect because of forward flexion of the trunk and pain in the low back and/or legs, typically occurs in the setting of decreased lumbar lordosis as a result of distraction instrumentation of the spine for scoliosis, vertebral fracture, or degenerative disease. Focus was placed on determining the factors responsible for the development and/or persistence of the flat back syndrome in these patients despite maintenance of, or partial operative restoration of, lumbar lordosis. Considering the essential role that the trunk extensor musculature plays in maintaining upright posture, it may be that a new onset of weakness (postpolio syndrome) in this musculature represents a major contributing factor to the flat back syndrome in these patients. Spine surgeons considering operative procedures in patients with a remote history of paralytic poliomyelitis should be aware of the possible increased risk of the flat back syndrome in this population of patients.

Back Pain↗